How do annabeth and grover prove themselves to be real friends to percy jackson?

How do Annabeth and Grover prove themselves to be real friends to Percy? They both offered to stay in the Underworld. What is the power of the pearls? It will protect one person and transport them where they wish to go.Explanation:

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."